Elucidating the molecular drivers of prostate development using iPSC-derived organoids

Abstract

PhD ThesisProstate cancer (PCa) is one of the leading causes of death among men in developed countries. Advances in uncovering the mechanisms of this disease have in part been hampered by the absence of a suitable human model that incorporates the complexity and variability of the disease. Inherent limitations of current models have prevented a complete understanding of PCa. Recently, patient-derived prostate organoids have emerged as an additional tool to complement current models. However, the process of prostate organoid generation using primary tissue can be inefficient. To overcome this and other limitations of current prostate organoid methodologies, our group developed an alternative method to produce prostate organoids using induced pluripotent stem cells (iPSCs). However, the process of prostate differentiation is complex and has yet to be fully elucidated. This research focused on optimizing the in vitro conditions of iPSC differentiation to prostate organoids, with a focus on using neonatal seminal vesicle mesenchyme (SVM) to induce prostate specification. The optimal culture conditions to produce prostate organoids were established and methods to maintain and analyse organoids were standardized. Organoids generated were composed of luminal, basal, and stromal cells, with rare neuroendocrine and stem cells. Additionally, we sought to elucidate the molecular drivers of prostate induction through RNA-sequencing analyses of the early rat prostate and inductive SVM. We were able to uncover candidate genes enriched in the inductive mesenchyme that may be involved with prostate specification. We were also able to identify genes and pathways in the epithelium that are likely responsible for responding to cues from the mesenchyme, leading to prostate differentiation. The candidates found in this research can be evaluated for their ability to improve iPSCs to prostate differentiation, which may eliminate the need for rodent mesenchymal tissue in this model. Furthermore, the datasets generated in this research can be further interrogated to better understand the reactivation of developmental genes in adulthood, leading to PCa